[AKG240mkII]

Quote:

Do amps really have different signatures?

 
Yes, some of them really do .
The point is..
A : They shouldn't !!
B : When they do anyways, it is possible to objectively determine WHY !!!

 

[dvw]

Quote:

 
Yes, some of them really do .
The point is..
A : They shouldn't !!
B : When they do anyways, it is possible to objectively determine WHY !!!

Short and precise. Best answer after 7 pages.

 

[Siva108]

Okay bigshot, I looked at a couple reviews of two different FiiO amps, the higher end one ended up measuring flatter.
 
Why would this be?

 

[bigshot]

Audibly flatter? What are the specs?

The way the specs are listed can make a difference too. My receiver has +0/-3dB on the frequency response, which might be audible, but that is from 10Hz to 100kHz. That's wider than they needed to test, and I'd bet the -3dB deviation is at the ends of the spectrum where you can't hear it.

 

[Siva108]

I posted links but they were deleted since the guy's site isn't allowed here.
 
I'll PM you the links.
 
Its the FiiO E9 and the E11 btw. The E11 only has some roll off in the bass region and its relatively flat from there, but the E9 has roll off both in the bass region and the upper treble region.

 

[bigshot]

I see what you're looking at now. That graph goes beyond the range of human hearing. If you line up 20Hz to 20kHz on those graphs you'll see it's stone flat in that range. It doesn't matter if there is a rolloff beyond that range unless you are a bat.

Both those amps would sound exactly the same based on tjose measurements.

I didn't know there were banned sites here. Why is that?

 

[jcx]

whatever the real resons for banning the individual here - it does look stupid to keep censoring links to objective information on headphone amplification, a popular diy headphone project amp that has to hinted arouund so people can find it with Google

 

[Steve Eddy]

Quote:

I didn't know there were banned sites here. Why is that?

 
You think that's bad, you can't even mention this particular person's name here. It's like how the old Soviet Union used to "disappear" people.
 
se

 

[mikeaj]

I think the restriction on the name was lifted, or they just stopped enforcing.
 
Regardless, at some certain place on the Internet that I'm sure you already found, you can easily find other issues between the E9 and E11 that might make them sound different in certain scenarios.  Most notably, the E9 has a lot more output impedance.  It also has more noise, which you actually might notice with those really sensitive multi-driver balanced armature IEMs with great isolation, which would of course be already be screwed over by the output impedance.
 
But yes, FR difference when tested into resistors or a line input certainly doesn't seem like an issue.

 

[Happy Camper]

Quite an impression for such passion.

Oh, I took my HE-6 in to give a listen to some speaker amps at my preferred A/V shop today. I spun a few discs/files on a Marantz, PrimaLuna and three Sim models. No scientific protocols were considered, just favorite music and the volume control. I wanted to hear this for myself.

 

[bigshot]

.Again, the exceptions aren't the point. How the amp sounds with mismatched IEMs is pretty much irrelevant.

88dB on the noise isn't going to be audible in any real world applicationlp. Impedence all depends on what headphones you plan to use with them. Properly matched to headphones, those two amps are going to sound identical.

 

[Anaxilus]

http://www.head-fi.org/t/528149/ibasso-pb-2-pelican-fully-balanced-portable-db-2-dac-hiflight-recommended-op-amps-page-16/750#post_8669168

 

[bigshot]

That is a very nice bit of creative writing. I especially like the vocabulary. It's like poetry. Amazing how he could memorize the sound of an amp he had never heard before and identify it by name with a break of a couple of minutes between samples. Almost unbelievable. No, not almost...

 

[Anaxilus]

Quote:

That is a very nice bit of creative writing. I especially like the vocabulary. It's like poetry. Amazing how he could memorize the sound of an amp he had never heard before and identify it by name with a break of a couple of minutes between samples. Almost unbelievable. No, not almost...

Much like the biased vocabulary used in the 'authoritative' oft linked garbage often linked as biblical reference here?  No, not nearly.  Sorry that reading evidence of all things not sounding the same makes you so defensive on the verge of tears.  Not unbelievable though wrt those w/ unshakeable, absolute religious views spewing myopic altruisms based on flawed, uncomprehensive 'tests' masquerading as science.  Well, at least we all know all bluray and dvd players look the same, oh wait....   

 

[stv014]

Quote:

That is a very nice bit of creative writing. I especially like the vocabulary. It's like poetry. Amazing how he could memorize the sound of an amp he had never heard before and identify it by name with a break of a couple of minutes between samples. Almost unbelievable. No, not almost...

 
Assuming that the blind test is valid (it may or may not be), I wonder if the following:
 
"This momentary aberrant behavior seems to occur whenever there's a particularly loud high frequency signal during an instant of high-complexity, where the DAC has a lot of work to do to sort everything out.  It's as if the ODAC just gives up, momentarily, and renders those instantaneous high frequencies like two blocks of styrofoam being rubbed together - to produce a very short in duration, but very loud distortion of information that the LX and the PB2 have no difficulty rendering cleanly."
 
is related to inter-sample clipping, as tested here on two sound cards, one with a CS4398 DAC, and another with PCM1792A (ironically, it is the more expensive latter one that fails) ? With my test sample, which is a mix of a 11.025 kHz sine wave at an amplitude of 0.8284 and 45 degrees phase, and a 15.025 kHz sine wave at 0.4142 amplitude and 0 phase, the problem is plainly audible on a DAC that fails. However, it is a rather unrealistic "worst case" signal and a similar effect is much less likely to occur at an audible level in typical music. When I mentioned this issue to the designer of the ODAC, he argued that it would never be audible with real music; from this response, and the fact that clipping problems are not easy to avoid with the ES902x DAC chips (as evidenced by the NuForce uDAC2), I suspect that the ODAC would fail my test, too.
 
Then again, maybe there was some more trivial problem, like the USB power not meeting the specs, and the DAC clipping already below 0 dBFS. Or the input stage of the iBasso amplifier clipping the output of the ODAC, which was the loudest of the three DACs tested. In any case, the subjective description of the problem sounds like some sort of clipping issue to me.